The present invention relates to a passenger number sensor system which measures the number of passengers passing through a wide door of a bus or the like vehicle even when a plurality of passengers may pass through the wide door at the same time.
In these days, a passenger number sensor system has been widely used as a suitable means for measuring the number of passengers when a person who counts the number of passenger passing through a desired door or gate cannot visually see the door or gate directly or when it is difficult to manually count the passenger number because of too many passengers.
A prior art passenger number sensor system will be detailed with reference to the attached drawing.
Referring to FIG. 3, there is shown a block diagram of a schematic arrangement of a prior art passenger number sensor system.
In FIG. 3, a differential infrared-ray sensor 1, which detects a change in the temperature of a light reception zone and generates a pulse signal corresponding thereto, is usually disposed in the upper part of a place for measurement of the number of passengers passing therethrough. A counter 2 counts up + "1" whenever receiving a pulse signal from the infrared ray sensor 1. Reference number 3 denotes a passenger who is passing through the passenger-number measurement place.
Explanation will next be made as to the operation of the above prior art passenger-number sensor system. When the passenger 3 passes through the passenger-number measurement place, the infrared ray sensor 1 senses a temperature change caused by the absorption of infrared rays issued from the infrared ray sensor 1 by the passenger 3 and sends a pulse signal to the counter 2. The counter 2, whenever receiving the pulse signal from the sensor 1, recognizes the passage of the passenger 3 and counts up + "1" to accumulatively measure the number of passengers passing through the measurement place.
As has been explained above, the prior art passenger-number sensor system can measure the number of passengers passing through the measurement place, under the condition that the passenger 3 can pass only one at a time through the measurement place where the infrared ray sensor 1 is installed.
However, the above prior art passenger-number sensor system has had such a problem that, since the counter 2 counts up + "1" constantly for measurement of the number of passengers, for example, even in the case where the system is used for such a wide door of a bus that allows a plurality of the passengers 3 to pass through the wide door laterally side by side at a time, the system may sense the passage of the plurality of the passengers 3 as a single temperature change and erronesouly judge it as the passage of the single person, whereby it is impossible to measure the accurate number of such passengers.